• Korean Journal of Food Science and Technology
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• v.29 no.4
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• pp.710-715
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• 1997

Inactivation of lipoxygenase activity in Chinese cabbage was shown after salting and heat treatments. Crude lipoxygenase was obtained from treatment of $(NH_{4})_{2}SO_{4}$. Lipoxygenase activity in Chinese cabbage was about 50% after 20 hrs of salting in 13% (w/v) concentration. After heating at $90^{\circ}C$ for 15 min, residual activity of lipoxygenase was about 50%. Inactivation of lipoxygenase was highly accelerated by increasing temperature and heating time. Decimal reduction time (D-value) were 42, 20 and 14 min at 70, 80 and $90^{\circ}C$, respectively. When cabbage was soaked in 0.05 M $CaCl_{2}$ and heated at $55^{\circ}C$ for 1.5 hr, higher activity of crude lipoxygenase was found compared with the heat treatment without $CaCl_{2}$.

• Food Science and Biotechnology
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• v.16 no.2
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• pp.255-259
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• 2007

The effects of temperature heating-up rate and pressure building-up phase on the inactivation of Listeria innocua ATCC 33090 were evaluated in buffered peptone water. The number of L. innocua was reduced by 5.57 and 6.52 log CFU/mL during the nonisothermal treatment (the come-up time followed by isothermal process) and the isothermal treatment, respectively, at $60^{\circ}C$. When compared to the isothermal treatment (0.76$33.2^{\circ}C/min$ of temperature heating-rate. The effect of the combined high pressure and thermal processing on the inactivation of L. innocua increased with increasing pressure and temperature. At all temperature levels from 40 to $60^{\circ}C$ under 700 MPa, L. innocua was not detected by enrichment culture (>7 log reduction).

• Applied Biological Chemistry
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• v.20 no.1
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• pp.101-104
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• 1977

Lipase from Geotrichum candidum was heat inactivated in 0.1M phosphate buffer solution. The thermal inactivation followed first order kinetics for the range of temperatures $50^{\circ}-80^{\circ}C$ except at $50^{\circ}C$. The changes in enthalpy, entropy and Gibbs free energy at $60^{\circ}C$ were 120.4 kJ/mol, 73.0 J/mol K and 96.9 kJ/mol respectively a value of $19^{\circ}C$(Geotrichum candidum lipase) is greater than that of lipases from milk and pancreas. The effect of detergents, lecithin and linoleic acid or the thermal inactivation of lipase was found to be negligible.

• Journal of Applied Biological Chemistry
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• v.59 no.1
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• pp.69-74
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• 2016

The objective of this study was to examine the combined effect of fumaric acid with mild heat on the inactivation of microorganisms on spinach. Spinach leaves were inoculated with Escherichia coli O157:H7 and Listeria monocytogenes. Based on the results of single treatment of fumaric acid (0.1, 0.3, and 0.5%) or mild heat (40, 50, and $60^{\circ}C$) regarding the inactivation of the inoculated bacteria, the optimal condition for the combined treatment was suggested to be 0.5% fumaric acid and mild heat treatment at $50^{\circ}C$ for 5 min. The combined treatment of fumaric acid with mild heat caused 2.53 and 2.62 log reductions of the populations of L. monocytogenes and E. coli O157:H7, respectively. In addition, during storage of fresh spinach at $4^{\circ}C$ for 12 d, the combined treatment reduced initially the populations of total aerobic bacteria by 2.77 log CFU/g compared with the control. In particular, after 12 d of storage, the population of total aerobic bacteria for the combined treatment sample was 4.84 log CFU/g, whereas the control sample had 6.66 log CFU/g. Color and vitamin C content of spinach samples were not altered significantly by the combined treatment during storage. These results indicate that the combined treatment of fumaric acid with mild heat is an effective method to control microorganisms on spinach during storage.

• Journal of Aquaculture
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• v.12 no.3
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• pp.167-173
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• 1999

Blocking the 1st mitotic cleavage was performed in mud loach (Misgurmus mizolepis) using UV-irradiated cyprinid loach (M. anguillicaudatus) sperm and ternal shocks Optimum UV range for inactivation of cyprinid loach sperm and thermal shocks. Optimum UV range for inactivation of cyprinid loach sperm was between 3,150 to 4,050 ergs/m$m^2$. Heat shock treatment ($41^{\circ}C$ for 3mins) with various treatment initiation times ranged from 22 to 50 min post insemination resulted wide range of success for induced gynogenesis. Best result was obtained when haploid egges were shocked at 28 min after insemination (corresponding to metaphase division of the 1st cleavage); 26% of total eggs inseminated were viable diploid gynogens. The hatching success and early survival of the both meiotic and mitotic gynogenetic groups were significantly lower than those of control crosses (P<0.05). Maternal origin of induced gynogenetic mud loach was verified by multi-locus DNA fingerprinting.

• Journal of Ginseng Research
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• v.9 no.1
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• pp.72-85
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• 1985

Attempts were made to see if feeding of ginseng ethanol extract could affect proper- ties of rat brain lactate dehydrogenase such as specific activity, heat stability, Km for substrate, inactivation by 3-bromopyruvate and trypsin, and immune response. The following results were obtained. Specific activity of LDH was observed to reach maximum in 5 month after birth and then decrease steadily. However, that of LDH from rat fed with ginseng ethanol extract was found in rat fed with ginseng ethanol extract. 3-bromopyruvate was shown to inactivate LDH-5 from old rat fed. Inactivation of LDH-5 by trypsin was remarkable in old rat fed. Km value for pyruvate in old rat fed was remarkably decreased. Cumulative results suggest that ginseng ethanol extract could affect conformational change of LDH responsible for altered properties through unknown mechanism.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.4
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• pp.301-304
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• 1990

Factors affecting thermal inactivation and reactivation of korean radish peroxidase were inves-tigated,. The enzyme was stable below pH4.0 and above pH 8.0 The thermostablity of the enzyme was increased by addition of glucose sodium chloride and albuminl The inactivated enzyme by heat treatment was reactivated at room temperaturem The optimal pH for reactivation of the enzyme was pH of 9.0 The reactivation rate of the enyme was not afected by addition of glucose sodium chloride and albumin, The reactivation was completely inhibited by addition of sulfhydryl reagent such as dithiothreitol.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.1016-1020
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• 1997

Treatments of irradiation alone and/or in combination with heat were investigated for the sterilization of Escherichia coli O157: H7. D values of the strain were 129.2 min at $50^{\circ}C$, 27.1 min at $55^{\circ}C$, and 2.4 min at $60^{\circ}C$. The survival effect of E. coli O157:H7 during heating at various media was investigated. On heating at temperature of $60^{\circ}C$ for 10 min, the strain was generally more resistant in the media containg such chemical substrates such as 0.03 M cysteine, 1% sodium citrate or 5% sucrose, whereas this strain was appeared weaker in the chemical substrates added group such as 1% meat extract, 1% casein or 1% casamino acid. In the case of irradiation alone, $D_{10}$ value of E. coli O157:H7 was 0.116 kGy, and inactivation factors were $17{\sim}25$ at doses of 2 to 3 kGy. Pre-and post-irradiation heating showed the same $D_{10}$ value about 0.07 kGy. And Inactivation factors were $25{\sim}41$ at doses of 2 to 3 kGy. Therefore, combination treatment with heat and irradiation significantly increased in inactivation rate by increasing radiation sensitivity of E. coli O157:H7.

• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.858-864
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• 2000

The purpose of the present study was to examine the efficacy and mechanism of the fraction IV cold ethanol fractionation and pasteurization ($60^{\circ}C$ heat treatment for 10h) steps, involved in the manufacture of albumin from human plasma, in the removal and/or inactivation of blood-born viruses. A variety of experimental model viruses for human pathogenic viruses, including the Bovine viral diarrhoea virus (BVDV), Bovine herpes virus (BHV), Murine encephalomyocarditis virus (EMCV), and Porcine parvovirus (PPV), were selected for this study. Samples from the relevant stages of the production process were spiked with the viruses, and the amount of virus in each fraction was then quantified using a 50% tissue culture infectious dose ($TCID_{50}$). The mechanism of reduction for the enveloped viruses (BHV and BVDV) during fraction IV fractionation was inactivation rather than partitioning, however, it was partitioning in the case of the non-enveloped viruses (EMCV and PPV). The log reduction factors achieved during fraction IV fractionation were ${\geq}6.9$ BHV, $\geq5.2$ for BBDV, 4.9 for EMC, and 4.0 for PPV. Pasteurization was found to be a robust and effective step in inactivating the enveloped viruses as well as EMCV. The log reduction factors achieved during pasteurization were $\geq7.0$ for BHV, $\geq6.1$ for BVDV, $\geq6.3$ for EMCV, and 1.7 for PPV. These results indicate that the production process for albumin has sufficient virus-reducing capacity to achieve a high margin for virus safety.

• Food Engineering Progress
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• v.15 no.4
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• pp.398-403
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• 2011

A dielectric barrier discharge plasma (DBDP) treatment system was fabricated and the optimum operating conditions for the plasma generation were determined in order to explore the potential of cold plasma as a non-thermal proessing technology. The microbial inactivation performance of the system was also evaluated against Staphyloocus aureus. The system consisted of power supply, transformer, electrode assembly and sample treatment plate. The input power was 220 V single phase AC and amplified to 10.0-50.0 kV on a transformer. A pulsed sine wave of frequency 10.0-50.0 kHz was introduced to the electrode embedded in ceramic as a dielectric barrier material in order to generate plasma at atmospheric pressure. Higher currents and consequently greater power were required for the plasma generation as the frequencies increased. A homogeneous and stable plasma was generated at currents of 1.0-2.0, and frequencies of 32.0-35.3 kHz. The optimum electrode-gaps for the plasma generation were 1.85 mm without loaded samples. More power was consumed as the electrode-gaps increased. The practically optimum electrode- gap was, however, 2.65 mm when samples were treated on slide-glasses for microbial inactivation. The maximum temperature increase after 10 min treatment was less than 20$^{\circ}C$, indicating no microbial inactivation effect by heat and thereby insuring a non-thermal method. The DBDP inactivation effect against Staphyloocus aureus increased linearly with treatment time up to 5 min, but plateaued afterward. More than 5 log reduction was achieved by 10 min treatment at 1.25 A.